Pèlegrin A, Folli S, Buchegger F, Mach J P, Wagnières G, van den Bergh H
Institute of Biochemistry, University of Lausanne, Epalinges, Switzerland.
Cancer. 1991 May 15;67(10):2529-37. doi: 10.1002/1097-0142(19910515)67:10<2529::aid-cncr2820671024>3.0.co;2-b.
To improve the detectability of tumors by light-induced fluorescence, the use of monoclonal antibodies (MoAb) as carriers of fluorescent molecules was studied. As a model for this approach, the biodistribution of an anticarcinoembryonic antigen (CEA) MoAb coupled to fluorescein was studied in mice bearing a human colon carcinoma xenograft. In vitro, such conjugates with fluorescein-MoAb molar ratios ranging from four to 19, doubly labeled with 125I, showed more than 82% binding to immobilized CEA. In vivo, conjugates with a fluorescein-MoAb molar ratio of ten or less resulted in a tumor uptake of more than 30% of the injected dose of radioactivity per gram tumor at 24 hours. Tumor to liver, kidney, and muscle ratios of 20, 30 and 72, respectively, were obtained 48 hours after injection of the 125I-MoAb-(fluorescein)10 conjugate. The highest fluorescence intensity was always obtained for the tumor with the anti-CEA MoAb conjugate; whereas in control mice injected with fluoresceinated control immunoglobulin G1, no detectable increase in tumor fluorescence was observed. To compare these results with a classically used dye, mice bearing the same xenografts received 60 micrograms of Photofrin II. The intensity of the fluorescence signal of the tumor with this amount of Photofrin II was eight times lower than that obtained after an injection of 442 ng of fluorescein coupled with 20 micrograms of MoAb, which gave an absolute amount of fluorescein localized in the tumor of up to 125 ng/g of tumor. These results illustrate the possibility of improving the specificity of in vivo tumor localization of dyes for laser-induced fluorescence photodetection and phototherapy by coupling them to MoAb directed against tumor markers.
为了通过光诱导荧光提高肿瘤的可检测性，研究了使用单克隆抗体（MoAb）作为荧光分子载体的情况。作为该方法的模型，研究了与荧光素偶联的抗癌胚抗原（CEA）单克隆抗体在携带人结肠癌异种移植瘤的小鼠体内的生物分布。在体外，这种荧光素 - 单克隆抗体摩尔比为4至19且用125I双重标记的偶联物，与固定化CEA的结合率超过82％。在体内，荧光素 - 单克隆抗体摩尔比为10或更低的偶联物在24小时时导致肿瘤摄取超过每克肿瘤注射剂量放射性的30％。注射125I - 单克隆抗体 - （荧光素）10偶联物48小时后，肿瘤与肝脏、肾脏和肌肉的比率分别为20、30和72。使用抗CEA单克隆抗体偶联物时，肿瘤总是获得最高的荧光强度；而在注射荧光素化对照免疫球蛋白G1的对照小鼠中，未观察到肿瘤荧光有可检测到的增加。为了将这些结果与经典使用的染料进行比较，携带相同异种移植瘤的小鼠接受了60微克的二血卟啉醚。该剂量的二血卟啉醚产生的肿瘤荧光信号强度比注射442纳克荧光素与20微克单克隆抗体后获得的强度低8倍，后者在肿瘤中定位的荧光素绝对量高达每克肿瘤125纳克。这些结果说明了通过将染料与针对肿瘤标志物的单克隆抗体偶联，提高用于激光诱导荧光光检测和光疗的染料在体内肿瘤定位特异性的可能性。
